diff --git a/tools/ChangelogGenerator/changelog_generator.py b/tools/ChangelogGenerator/changelog_generator.py
index f057c0f998..85a784f318 100644
--- a/tools/ChangelogGenerator/changelog_generator.py
+++ b/tools/ChangelogGenerator/changelog_generator.py
@@ -254,13 +254,15 @@ def main(tag_name=None, latest=None):
             continue
         git_addition_command = rf'git log {commit_hash} --no-walk --pretty=format:"%b"'
         addition = call_command(git_addition_command)
-        coauthors = []
+        coauthors = set()
         for coauthor in re.findall(r"Co-authored-by: (.*) <(?:.*)>", addition):
             if coauthor in contributors:
-                coauthors.append(contributors[coauthor])
+                coauthors.add(contributors[coauthor])
+            elif coauthor in contributors.values():
+                coauthors.add(coauthor)
             else:
                 print(f"Cannot get coauthor: {coauthor}.")
-        raw_commits_info[commit_hash]["coauthors"] = coauthors
+        raw_commits_info[commit_hash]["coauthors"] = list(coauthors)
 
     git_skip_command = rf'git log {latest}..HEAD --pretty=format:"%H%n" --grep="\[skip changelog\]"'
     raw_gitlogs = call_command(git_skip_command)